Annals of Clinical Microbiology, The official Journal of the Korean Society of Clinical Microbiology


Weeks in Review


Weeks to Publication
Indexed in KCI, KoreaMed, Synapse, DOAJ
Open Access, Peer Reviewed
pISSN 2288-0585 eISSN 2288-6850

March, 2011. Vol. 14 No. 1.

Original article

Clinical Aspects of Bacterial Meningitis in Cerebrospinal Fluid Culture Positive Patients in a Tertiary Care University Hospital

Min Jin Kim, Song Mi Moon, Tae Sung Park, Jin-Tae Suh, Hee Joo Lee

Ann Clin Microbiol 2011 March, 14(1): 1-6. Published on 20 March 2011.

Background: There have been previous clinical research studies on clinical manifestations of meningitis in adults or children; however, few have focused on including both groups and none on the causative organism and its susceptibilities to antibiotics. Here we describe the distribution of causative organism and its antibiotic susceptibilities of meningitis from spinal fluid positive patients of a university hospital. 

Methods: Cases of spinal fluid culture results from admitted patients in Kyung Hee Medical Center from July 2004 to June 2009 were analyzed retrospectively by their medical records and laboratory results. 

Results: Ninety five cases of positive spinal fluid culture results were obtained and 25 cases fit the diagnostic criteria for bacterial meningitis. 5 cases were spontaneous meningitis and 20 were post cranial surgery meningitis. Among the 25 patients, fever was the most common clinical presentation (100%) and ventriculoperitoneal shunt was the most common causative procedure of post cranial surgery meningitis. Streptococcus pneumoniae for spontaneous meningitis and Acinetobacter species for post cranial surgery meningitis was identified as the most common causative organisms. 

Conclusion: Recurrent positive spinal fluid culture results of the same organism was found in expired patients due to post cranial surgery meningitis and also from the culture results of the wound and intra-cranial inserted instruments, suggesting post operative infection control is directly related to morbidity requiring adequate usage of antibiotics rather than empirical broad spectrum antibiotics.

[in Korean]

Original article

The Value of Serum Procalcitonin Level for Differentiation between Contaminants and Pathogens in Bacteremia

Hei Kyung Jin, Jae Yun Jang, Young Uh, Ohgun Kwon, Kap Jun Yoon, Hyo Youl Kim, Young Keun Kim

Ann Clin Microbiol 2011 March, 14(1): 7-12. Published on 20 March 2011.

Background: Bacteremia is a life-threatening infection, and prognosis is highly dependent on early recognition and treatment with appropriate antimicrobial agents. We investigated the diagnostic performance of serum procalcitonin (PCT) for differentiation between contaminants and true pathogens in blood cultures. 

Methods: Serum PCT, C-reactive protein (CRP) and blood culture were performed for 473 patients between February 2008 and October 2008. We retrospectively reviewed the patients’ clinical characteristics and laboratory results based on medical records. 

Results: The mean concentration of PCT was significantly different between the two negative and positive blood culture groups (6.45 ng/mL vs 28.77 ng/ mL, P<0.001). Procalcitonin levels were found to be markedly higher in those with Gram-negative bacilli (mean±SD; 59.58±67.00 ng/mL) bacteremia than in those with Gram-positive cocci (mean±SD; 17.75±42.88 ng/mL) bacteremia (P<0.001). The areas under the receiver operating characteristic curves (95% confidence interval) for PCT and CRP were 0.880 (0.820∼ 0.940) and 0.637 (0.538∼0.736), respectively. The use of a PCT level of 2 ng/mL as a cutoff value yielded an 83.6% positive predictive value and a 77.4% negative predictive value for the detection of bacteremia pathogens. 

Conclusion: Serum PCT is a helpful diagnostic marker for rapidly and accurately distinguishing between contaminants and pathogens in blood cultures.

[in Korean]

Original article

Evaluation of Automated Blood Culture System for Body Fluids Culture Other Than Blood

Tae Yeal Choi, Jung Oak Kang, Hyun Joo Pai

Ann Clin Microbiol 2011 March, 14(1): 13-17. Published on 20 March 2011.

Background: We investigated whether culture using an automated blood culture system enhances the recovery of bacteria and fungi from body fluids other than blood when compared to conventional solid media culture methods. 

Methods: A total of 734 specimens [ascites (n=457), bile (n=5), CAPD (n=28), CSF (n=32), joint fluids (n= 165), pericardial fluid (n=17), and pleural fluid (n=30)] were included in the study. Half of the volume of each specimen was inoculated directly into automated blood culture bottles (bioMeriux, Marcy-I’Etoile, France). The remaining volume was inoculated onto conventional solid media (sheep blood agar, chocolate agar, and phenylethyl alcohol agar) after centrifuging at 3,000 rpm for 10 min. 

Results: Clinically significant microorganisms were isolated from 62 specimens (8.5%) by automated blood culture and 61 specimens (8.3%) by the conventional solid media culture (kappa index: 0.81, 95% confidence interval: 0.75∼0.89). Contamination was observed in 11 (1.8%) of the automated blood culture specimens and 3 (0.4%) of the solid media culture specimens. The mean turnaround times of the automated blood cultures and the conventional solid media cultures were 3.7 and 2.8 days, respectively (P< 0.0001). 

Conclusion: Compared with conventional culture methods, no improvement in the recovery of clinically significant microorganisms was noted with the use of the automated blood culture system for the culture of body fluids other than blood.

[in Korean]

Original article

Prevalence and Clinical Characteristics of Mupirocin-Resistant Staphylococcus aureus

A-jin Lee, Hun-Suk Suh, Chang-Ho Jeon, Sang-Gyung Kim

Ann Clin Microbiol 2011 March, 14(1): 18-23. Published on 20 March 2011.

Background: Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) is a known risk factor for nosocomialtransmission and infection. In an effort to mitigate this problem, topical mupirocin has been widely used for clearing nasal carriage of MRSA. However, mupirocin resistance has become a world- wide concern due to increased use of the antibiotic. The aims of this study were to evaluate the clinical characteristics and prevalence of mupirocin resistance among clinical isolates of staphylococci and to investigate antimicrobial susceptibility. 

Methods: A total of 175 Saureus specimens recovered over a 4-month period from various body sites were tested for resistance to mupirocin and other antibiotics using the Vitek2 automated system. The presence of the mupA gene was assessed in isolates exhibiting resistance to mupirocin and in other selected organisms. The clinical characteristics of the isolates were also reviewed. 

Results: Of the 175 Saureus isolates, 9.1% (16/175) were resistant to mupirocin, with 1.7% (3/175) having high-level resistance (HR) and 7.4% (13/175) having low-level resistance (LR). Patients with HR-mupirocin- resistant Saureus had a longer duration of hospitalization (P=0.026). Of the 13 LR-mupirocin-resistant S. aureus strains, 11 had identical antibiogram patterns. The mupA gene was detected only among HR isolates. 

Conclusion: The rate of mupirocin resistance in the Saureus isolates was high. The spread of mupirocin- resistant S. aureus may be due to nosocomial infection.

[in Korean]

Original article

Comparison of Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing Breakpoints for β-Lactams in Enterobacteriaceae Producing Extended-Spectrum β-Lactamases and/or Plasmid-Mediated AmpC β-Lactamases

Wonkeun Song, Min-Jeong Park, Han-Sung Kim, Jae-Seok Kim, Hyun Soo Kim, Kyu Man Lee

Ann Clin Microbiol 2011 March, 14(1): 24-29. Published on 20 March 2011.

Background: In 2010, the Clinical and Laboratory Standards Institute (CLSI) revised breakpoints for cephalosporins and carbapenems and indicated that extended-spectrum β-lactamase (ESBL) testing is no longer necessary for Enterobacteriaceae. We compared the results of the CLSI 2010 and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) MIC breakpoints for Enterobacteriaceae producing ESBL and/or plasmid-mediated AmpC β-lactamase (PABL). 

Methods: A total of 94 well-characterized clinical isolates of Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Proteus mirabilis, Salmonella spp., Shigella spp., Citrobacter freundii, Enterobacter aerogenes, Enterobacter cloacae, and Serratia marcescens were analyzed. Of them, 57 were ESBL producers, 24 were PABL producers, and 13 were ESBL plus PABL co-producers. Broth microdilution MIC tests were performed for cefotaxime, ceftazidime, aztreonam, cefepime, and imipenem. 

Results: Among the 94 isolates containing ESBL and/ or PABL, the number of isolates that were susceptible to cefotaxime, ceftazidime, aztreonam, cefepime, and imipenem according to the CLSI 2010 vs. the EUCAST breakpoints were 4 (4.3%) vs. 4 (4.3%); 26 (27.7%) vs. 8 (8.5%); 37 (39.4%) vs. 14 (14.9%); 71 (75.5%) vs. 31 (33.0%); and 76 (80.9%) vs. 90 (95.7%), respectively. Of the 18 isolates that were not susceptible to imipenem according to the CLSI 2010 breakpoints, 13 isolates (72.2%) were P. mirabilis.

Conclusion: The CLSI 2010 MIC breakpoints without tests to detect ESBL and/or PABL for Enterobacteriaceae could be unreliable. Thus, special tests for ESBLs and AmpC β-lactamases are required to detect the resistance mechanisms involved.

Original article

Clinical Implications of Multiplex PCR Detection of Fastidious Microorganisms in Vaginitis Patients

Nae Yu, Mi-Kyung Lee

Ann Clin Microbiol 2011 March, 14(1): 30-35. Published on 20 March 2011.

Background: Bacterial vaginitis (BV) and Trichomonas vaginitis are the most frequently recurring infectious diseases in women. Therefore, accurate tests for post-treatment follow-up are required. A multiplex PCR assay allows for the simultaneous detection of multiple pathogens in a single specimen. In this study, we assessed the clinical implications of multiplex PCR detection of fastidious microorganisms causing vaginitis. 

Methods: A total of 216 vaginitis patients who presented to Chung-Ang University Yongsan Hospital with more than one positive result on multiplex PCR (Trichomonas vaginalis (TV), Neisseria gonorrhoeae (NG), Chlamydia trachomatis (CT), Ureaplasma urealyticum (UU), Mycoplasma genitalium (MG), Mycoplasma hominis (MH)) were retrospectively enrolled in this study. Each patient’s clinical symptoms, initial treatment and follow-up for BV, and other related test results were also retrospectively reviewed. 

Results: The most commonly reported symptom was abnormal discharge, followed by pruritis (73.1%), lower abdominal pain (38.4%), urination difficulties (13%), and others such as fever. According to the multiplex PCR results, there were 116 cases (35.8%) of MH, 86 cases (26.5%) of UU, 62 cases (19.1%) of CT, and 84 cases (38.9%) were mixed infections. Among those patients with single infections, treatment changed for 63 cases (65.6%) while treatment remained unchanged for 17 (17.7%) after PCR results were reported. 

Conclusion: The diagnosis of BV using multiplex PCR is clinically effective and the results of which can be incorporated in antibiotic selection for patients with multiple sexually transmitted diseases (STD). Multiplex PCR may be especially helpful in the diagnosis of patients in whom the differentiation of STD pathogens is difficult using traditional methods.

[in Korean]

Case report

A Case of a 63-bp Deletion in the mpt64 Gene of Mycobacterium tuberculosis Strains Which Showed False Negativity in the Immunochromatographic Assay

Chang Eun Yoon, Young Joon Hong, Jin Kyung Lee, Yoon Hwan Chang, Seok-Il Hong

Ann Clin Microbiol 2011 March, 14(1): 36-38. Published on 20 March 2011.

Mycobacterium tuberculosis complex (MTBC) is discriminated from non-tuberculous mycobacteria (NTM) via an immunochromatographic assay (ICA) which is based on the reactions of monoclonal antibodies against MPT64, one of the predominant proteins excreted by MTBC. Recently, the authors of the present study discovered SD TB-negative Mycobacterium tuberculosis strains. In addition, sequence analysis of the mpt64 genes in these strains was performed and showed a deletion of 63 bp from nucleotides 196 to 258. In cases of MPT64-negative mycobacterium, the authors recommend performing TB PCR for correct diagnosis.

[in Korean]